From the IETF's Differentiated Services (DiffServ) Work Group's site:
The differentiated services approach to providing quality of service in networks employs a small, well-defined set of building blocks from which a variety of aggregate behaviors may be built. A small bit-pattern in each packet, in the IPv4 TOS octet or the IPv6 Traffic Class octet, is used to mark a packet to receive a particular forwarding treatment, or per-hop behavior, at each network node.
Examples of DiffServ-based services include the Premium IP and "Less-than Best Effort" (LBE) services available on GEANT/GN2 and some NRENs.
– Main.TobyRodwell - 28 Feb 2005
-- Main.SimonLeinen - 15 Jul 2005